Sealant Material Composition and Pneumatic Tire

Abstract

A sealant material composition forming a sealant layer of a pneumatic tire provided with the sealant layer on a tire inner surface is prepared by blending from 1 part by mass to 40 parts by mass of a crosslinking aid and from 50 parts by mass to 400 parts by mass of a liquid isobutylene-isoprene copolymer having a molecular weight from 10000 to 60000 per 100 parts by mass of a halogenated butyl rubber.

1 . A sealant material composition forming a sealant layer of a pneumatic tire provided with the sealant layer on a tire inner surface, the sealant material composition being prepared by blending from 1 part by mass to 40 parts by mass of a crosslinking aid and from 50 parts by mass to 400 parts by mass of a liquid isobutylene-isoprene copolymer having a molecular weight from 10000 to 60000 per 100 parts by mass of a halogenated butyl rubber. 
     
     
         2 . The sealant material composition according to  claim 1 , wherein the crosslinking aid is a quinone dioxime compound. 
     
     
         3 . The sealant material composition according to  claim 1 , wherein a ratio A/B of a blending amount A of the crosslinking aid to a blending amount B of the liquid isobutylene-isoprene copolymer is from 1/10 to 10/1. 
     
     
         4 . The sealant material composition according to  claim 1 , wherein an amount from 1 part by mass to 40 parts by mass of an organic peroxide is blended per 100 parts by mass of the halogenated butyl rubber. 
     
     
         5 . A pneumatic tire comprising: a tread portion having an annular shape extending in a tire circumferential direction; a pair of sidewall portions disposed on both sides of the tread portion; and a pair of bead portions disposed on an inner side of the sidewall portions in a tire outer diameter direction, and having at least a sealant layer made of the sealant material composition according to  claim 1  on an inner side of an innerliner layer in a tire radial direction of the tread portion, the innerliner layer comprising a halogenated butyl rubber. 
     
     
         6 . The pneumatic tire according to  claim 5 , wherein the sealant layer has a thickness from 0.5 mm to 5.0 mm. 
     
     
         7 . The pneumatic tire according to  claim 5 , wherein the sealant layer is formed by attaching a sheet-like molded sealant material made of the sealant material composition entirely around a circumference of a tire inner surface. 
     
     
         8 . The pneumatic tire according to  claim 5 , wherein the sealant layer is formed by spirally attaching a string-like or band-like molded sealant material made of the sealant material composition to a tire inner surface. 
     
     
         9 . The pneumatic tire according to  claim 5 , wherein a center position of the sealant layer in a tire lateral direction is arranged within a range of ±10 mm in the tire lateral direction from a tire equator. 
     
     
         10 . The pneumatic tire according to  claim 5 , wherein a plurality of belt layers are embedded in the tread portion, a layer having a smallest belt width of the plurality of belt layers is a minimum belt layer, a layer having a largest belt width of the plurality of belt layers is a maximum belt layer, a distance from the tire equator to an end portion of the minimum belt layer is La, a distance from the tire equator to an end portion of the maximum belt layer is Lb, a distance from the tire equator to an end portion of the sealant layer in the tire lateral direction is Lc, and the distances La, Lb, Lc satisfy a relationship La≤Lc≤1.05×Lb. 
     
     
         11 . The sealant material composition according to  claim 2 , wherein a ratio A/B of a blending amount A of the crosslinking aid to a blending amount B of the liquid isobutylene-isoprene copolymer is from 1/10 to 10/1. 
     
     
         12 . The sealant material composition according to  claim 11 , wherein an amount from 1 part by mass to 40 parts by mass of an organic peroxide is blended per 100 parts by mass of the halogenated butyl rubber. 
     
     
         13 . A pneumatic tire comprising: a tread portion having an annular shape extending in a tire circumferential direction; a pair of sidewall portions disposed on both sides of the tread portion; and a pair of bead portions disposed on an inner side of the sidewall portions in a tire outer diameter direction, and having at least a sealant layer made of the sealant material composition according to  claim 12  on an inner side of an innerliner layer in a tire radial direction of the tread portion, the innerliner layer comprising a halogenated butyl rubber. 
     
     
         14 . The pneumatic tire according to  claim 13 , wherein the sealant layer has a thickness from 0.5 mm to 5.0 mm. 
     
     
         15 . The pneumatic tire according to  claim 14 , wherein the sealant layer is formed by attaching a sheet-like molded sealant material made of the sealant material composition entirely around a circumference of a tire inner surface. 
     
     
         16 . The pneumatic tire according to  claim 14 , wherein the sealant layer is formed by spirally attaching a string-like or band-like molded sealant material made of the sealant material composition to a tire inner surface. 
     
     
         17 . The pneumatic tire according to  claim 16 , wherein a center position of the sealant layer in a tire lateral direction is arranged within a range of ±10 mm in the tire lateral direction from a tire equator. 
     
     
         18 . The pneumatic tire according to  claim 17 , wherein a plurality of belt layers are embedded in the tread portion, a layer having a smallest belt width of the plurality of belt layers is a minimum belt layer, a layer having a largest belt width of the plurality of belt layers is a maximum belt layer, a distance from the tire equator to an end portion of the minimum belt layer is La, a distance from the tire equator to an end portion of the maximum belt layer is Lb, a distance from the tire equator to an end portion of the sealant layer in the tire lateral direction is Lc, and the distances La, Lb, Lc satisfy a relationship La≤Lc≤1.05×Lb.